SIZE 36-40 RUNS SMALL, CONSIDER SIZING UP.

"The legendary two-strap design from BIRKENSTOCK - the Arizona. Modeled on the cork original, this sandal is made from ultra lightweight and highly flexible EVA. These sandals are shock absorbing, waterproof, and skin-friendly. Wear them at the beach, in the garden, or around the gym and after workouts. It's the perfect addition to your classic BIRKENSTOCK sandals." -Birkenstock USA

EVA (ethylene vinyl acetate) is a high-quality, very light, elastic material with extremely good cushioning. Great for the beach or any other water activity.